In multi-part plastic cages which are connected together by ultrasonic welding, and which are strengthened by glass fibers, significant distortion results from the use of the sonotrode of the ultrasonic welding apparatus, as long as the sonotrode stays in direct contact with the melting plastic at the welding point.
It is known that cage parts and covers of plastic cages can be connected together by ultrasonic welding, whereby the free ends of each web or spacer and the opposite lying surface of the cover are provided with either a recess or with a cooperating projection, and that the recesses or apertures have dimensions such that a part of the projection is slidably received by the centering arrangement, so that the projection fills the aperture fully only after the ultrasonic welding process.
In such ultrasonic welding in the production of this type of cage, there are difficulties in that the plastification or plastifizing of the cage material by ultrasonic welding does not result in accurate centering and axial guiding of the cage parts themselves. In the production of the known cages, special arrangements must be provided for the centering and guiding of the cage parts, which causes the production to be more costly. In addition, prior cage connections are unsuitable especially for the reception of larger circumferential and radial forces, since the forces must be absorbed exclusively by the connection pins.